Electric reproducing apparatus for phonographs



A ril 15 1924. 1,490,764

W. H. BRISTOL ELECTRIC REPRODUCING APPARATUS FOR PHONOGRAPHS Filed June 1, 1922 Patented Apr. 15, 1924.

1,490,764 PATENT ounce.

WILLIAM H. BRISTOL, OF WATERJBUR-Y, CONNECTICUT.

ELECTRIC REPRODUCII NG APPARATUS FOR PHONOGRAI'HS.

Application filed June 1,

To all whom it may concern:

Be it known that I, WILLIAM H. BRIs'roL, a citizen of the United States, and a resident of Waterbury, in the county of New Haven and State of Connecticut, have invented certain new and useful Improvements in Electric Reproducing Apparatus for Phonographs, of which the following is a specification.

The invention relates to the reproduction of sound from a phonograph utilizing electrical transmitting and receiving devices, whereby the sound may be reproduced at a distance, if desired; and it has for its object, in the operation of such apparatus, to reduce greatly, if notentirely eliminate, undesirable and foreign sounds such as the scratching noise roduced by the stylus in travelling over the record. To effect this result, there is inserted in the electrical circuit between the transmitting and receiving devices a condenser of sufficient capacity to short-circuit substantially the transmitted sound waves of high frequency, such as the scratching sounds, but to allow of the free passage of sound waves below a predetermined frequency and which comprise those which it is desired to reproduce.

The nature of the invention, however, will best be understood when described in connection with the accompanying drawings, in which Fig. 1 represents a phonograph having an electric transmitter with stylus operatively associated therewith and a receiver connected to the transmitter thru an intermediate control device.

Fig. 2 is a diagrammatic view of the transmitting circuit.

Similar characters of reference designate corresponding parts thruout the several views.

Referring to the drawings, 10 designates a suitable casing containing suitable mechanism for rotating a turn-table 11 adapted to receive a record 12, in the grooves of which works the stylus 13 of a difierential telephone transmitter 14.- of any well-known or special construction. This transmitter is connected, preferably, to a control box 15 thru leads 16; and leads 17 are takentherefrom to a receiver device 18 of any welllrnown or special construction. There is also connected to the control box 15, as thru leads 19, a source of direct current supply as the battery 2Q.

1922. Serial No. 565,175.

The arrangement is more particularly set forth in Fig. 2 of the drawings; and, as

shown, the leads 16 from the transmitter are connected to one side of a transformer 21 contained within the control box 15, Whose other side is connected thru the leads 17 with the receiver device 18. In accordance with the invention, however, there is shunted across the secondary of the transformer 21 a condenser 22 of comparatively large capacity, (1mfd.); and the same is so proportioned to the other constants of the circuit as to be of the proper capacity to substantially short-circuit the waves of relatively high frequency and to-allow of the free passage of the sound waves of a frequency below a predetermined maximum. A compromise in this respect will be necessary; but it has been found that the foreign noises may be practically eliminated without interfering appreciably with the reproduction of the high-pitched sounds and a much more satisfactory rendering of the.

record is obtained. This feature is especially noticeable in connection with the re- 1. The combination with a phonograph and an electrical transmitter associated therewith for transmitting at audio frequency the sound produced thru engagement by the transmitter stylus with the phonoaph record; an electrical receiver memdr connected with the transmitter, and a source of electricity for same; of means for eliminating substantially the extraneous record sounds and comprising a condens= er included in circuit with the receiver member to short-circuit substantially the transmitted waves of relatively high-fre quency and thereby the extraneous sound waves but allow of the passage of the de sired sound waves transmitted from the record.

2. The combination with a phonograph and an electrical transmitter associated therewith for transmitting at audio frequency the sound produced thru engagement by the transmitter stylus with the phonograph record; an electrical receiver member connected with the transmitter, and a source of electricity for same; of means rear eliminating substantially the extraneous recof relatively high frequency and thereby the extraneous sound waves but allow of the passa e of the desired sound waves transmitte from the record.

3. The combination with a phonograph and an electrical transmitter associated therewith for transmitting at audio frequency the sound produced thru engagement by the transmitter stylus with the phonograph record; an electrical receiver member connected with the transmitter; a source of electricity and transformer for same; of means for eliminating substantially the extraneous record sounds and comprising a condenser shunted across the secondary of the transformer to short-circuit substantially the transmitted waves of relatively high frequency and thereby the extraneous sound waves but allow of the passage of the desired sound waves transmitted from the record.

"Signed at New York, in the county of New York and State of New York, this 25th day of May A. D. 1922.

WILLIAM H. BRISTOL. 

